"""
Description:
version:
Author: XiaoQiYan
Date: 2021-08-27 16:57:26
LastEditors: XiaoQiYan
LastEditTime: 2021-08-27 16:58:28
"""
while True:
    a = float(input("please enter your score:\n"))
    if 0 <= a < 60:
        level = "F"
    elif 60 <= a < 70:
        level = "D"
    elif 70 <= a < 80:
        level = "C"
    elif 80 <= a < 90:
        level = "B"
    elif 90 <= a <= 100:
        level = "A"
    else:
        print("您的输入有误!结束查询")
        break
    print("your level is %s:" % level)
